Dimethyl sulfoxide-induced dehydration of the intermembrane space of dipalmitoylphosphatidylcholine multilamellar vesicles: Neutron and synchrotron diffraction study

Abstract

Small-angle neutron scattering spectra of a polydispersed population of dipalmitoylphosphatidylcholine (DPPC) unilamellar vesicles in heavy water in the presence of dimethyl sulfoxide (DMSO) are analyzed by means of the separated form-factor method. An increase in the mole fraction of DMSO in water from 0 to 15% was shown to lead to an increase in the thickness of the bilayer to the characteristics repeat distances of DPPC multilamellar membranes. This fact is indicative of dehydration of the intermembrane space and a steric contact between adjacent DPPC bilayers at 15% mole fraction of DMSO.